1. Technical Field
The present invention relates to disposable diapers that can be used both as a tape-fastening type and an underpants type.
2. Related Art
An underpants type disposable diaper has joined portions on both sides that are formed by joining a front body part and a back body part on both side portions thereof, a waist opening and a pair of right and left leg openings, and the diaper is worn by letting both legs of a wearer pass through the waist opening and inserting the same into the leg openings.
A general underpants type diaper cannot be basically adjusted in size or shape. Therefore, resilient and elastic members are used to impart a resilient and elastic force to the diaper in a width direction so that the diaper can be changed in shape according to the body size of a wearer to thereby offer an increased fit.
Meanwhile, there are provided diapers called fastening type or tape-fastening type that are fitted to a wearer in a state where back and ventral parts are not joined, and fixed at leading ends of fastening tapes on both side portions of the back part to an external surface of the ventral part in use.
In addition, as described in Patent Document 1, there have been suggested two-way disposable diapers that can be used both as an underpants type and a fastening type. Such a disposable diaper has a rear back part, a front belt part extending from the rear back part to both sides in a width direction, and an absorbent main unit that can be folded from the rear back part through a crotch toward a front ventral side of a wearer. The diaper can be worn in a state where the front belt part winding around the waist and the folded absorbent main unit are fastened on the front ventral side of the wearer.
Patent Document 1: JP 2005-270359 A
However, such conventional diapers are difficult to adjust in size in a laterally balanced manner when a wearer lies on his/her side.
Specifically, if a wearer lies on his/her side, when an attempt is made to pull up a conventional diaper from upper and lower fastening tapes, the diaper can hardly be extended because a portion around the lower fastening tape is pressed and immovable against a waist of the wearer. In contrast, the diaper can be freely extended at a portion around the upper fastening tape that is not fixed. When being worn without size adjustment, the conventional diaper is extended approximately evenly around the waist. Therefore, if the evenly extended diaper is further extended only at one portion, the diaper may become significantly unbalanced on the right and left sides.
In addition, if a conventional two-way disposable diaper that can serve both as an underpants type and a fastening type, is used as a tape-fastening type, there is a problem that the diaper does not fit sufficiently to a wearer of a nonstandard body size because the tapes cannot be freely attached.